The present invention relates to friction clutches in general, and more particularly to improvements in clutch plates for use in friction clutches, especially in friction clutches of automotive vehicles. Still more particularly, the invention relates to improvements in clutch plates of the type wherein a first unit carries one or more friction linings which can be clamped between two pressure plates of the friction clutch and is angularly movable, within limits, relative to a second unit having a hub adapted to be connected to the input shaft of a change-speed transmission in an automotive vehicle. In such clutch plates, the first unit normally comprises a pair of disc members which surround the hub of the second unit and are rigidly connected to each other in axially spaced positions, and the hub of the second unit has a radially outwardly extending flange which is disposed between the disc members of the first unit.
As disclosed in German Offenlegungsschrift No. 3,205,039, a clutch plate can further comprise a third unit including two coaxial and rigidly interconnected intermediate discs which are disposed between the disc members of the first unit and flank the flange of the hub. The third unit is angularly movable with reference to the first and second units. Such angular movability of the three units with reference to each other is limited by a main damping unit for operation under load and by an auxiliary or idling damping unit for operation in the idling range.
The clutch plate of the aforementioned German printed publication further comprises a second flange which is secured to the flange of the hub and carries the intermediate discs of the third unit. The intermediate discs are disposed at the opposite sides of the second flange. A drawback of the just described clutch plate is that the combined weight of its constituents is quite pronounced, mainly or particularly due to the provision of the heavy second flange. This results in the generation of more pronounced stresses when the clutch plate is driven by the flywheel of an internal combustion engine. The bulk and weight of the clutch plate contribute to pronounced wear upon and rapidly affect the synchronization of the transmission which receives torque from the clutch plate. Moreover, the just described clutch plate comprises a substantial number of discrete parts which contributes to the initial and maintenance cost of the clutch embodying the clutch plate. Still further, the just discussed clutch plate does not allow for the selection of a wide variety of idling damping devices which normally comprise weak and small torsion springs.